Powered air cleaning system and air cleaning method

Abstract

A powered air cleaning system has a flow path extending through the system from an inlet to an outlet. A motor-driven fan is located along the flow path to draw particulate debris laden air into the inlet and rotate it about an axis to form a rotating flow that stratifies the debris laden air with the heaviest particles in the outermost orbits of the rotating flow. An ejector port ejects particulate debris laden air from the stratified rotating flow in the system. At least one de-swirl component located within the rotating flow aerodynamically redirects clean air from the innermost orbits of the stratified rotating flow toward the outlet to provide a positive airflow pressure out of the outlet. The system has a variable speed fan motor and an integrated controller for adjusting the speed of the motor and thereby the flow rate of clean air through the outlet of the system. The controller receives a signal that is a function of airflow requirements of a device supplied with clean air by the system. The system can be mounted above or below a hood housing an engine to be supplied with clean air.

1. A powered air cleaning system for supplying clean air with a positive airflow pressure out of an outlet of the system to an air inlet of a device with which the system is used, the system comprising:
 a flow path extending through the system from an inlet to an outlet; 
 a motor-driven fan located along the flow path to draw particulate debris laden air into the inlet and rotate it about an axis to form a rotating flow that stratifies the debris laden air with the heaviest particles in the outermost orbits of the rotating flow; 
 a separator-ejector chamber in the flow path downstream of the motor-driven fan, the outermost orbits of the orbits of the rotating flow riding on an outer wall of the separator-ejector chamber; 
 an ejector port located at a downstream end of the chamber for ejecting particulate debris laden air from the stratified rotating flow in the system, the outlet being located centrally within the downstream end of the chamber; 
 at least one de-swirl blade located within the rotating flow in the chamber and extending into the outlet for redirecting clean air from the innermost orbits of the stratified rotating flow in the chamber toward the outlet to provide a positive airflow pressure out of the outlet. 
 
     
     
       2. The air cleaning system according to  claim 1 , wherein a plurality of de-swirl blades are provided centered in the outlet. 
     
     
       3. The air cleaning system according to  claim 1 , wherein the motor-driven fan is a turbine-type fan with an impeller having a hub with blades thereon arranged in the flow path for rotation about the axis, the hub and the flow path at least in the area of the blades each progressively increasing in diameter in a downstream direction of the flow path. 
     
     
       4. The air cleaning system according to  claim 3 , wherein the impeller is formed of an assembly of an injection molded blade component and an injection molded hub component, and wherein features below the lower surface of blades on the blade component are formed on the hub component. 
     
     
       5. The air cleaning system according to  claim 1 , wherein the motor-driven fan includes a motor capable of rotating the fan at a speed on the order of 7000 rpm. 
     
     
       6. The air cleaning system according to  claim 1 , wherein the motor-driven fan includes a variable speed motor and an integrated controller for adjusting the speed of the motor and thereby the flow rate of clean air through the outlet of the system. 
     
     
       7. The air cleaning system according to  claim 6 , wherein the outlet is connected to an inlet of a device having variable airflow requirements, and wherein means are provided for signaling the controller as a function of the airflow requirements of the device for varying the speed of the motor and thereby the flow rate of clean air through the outlet to the device in accordance with the airflow requirements. 
     
     
       8. The air cleaning system according to  claim 7 , wherein the device has an internal combustion engine beneath a hood, and wherein said system is capable of being mounted in a selected one of under the hood and above the hood for cleaning air supplied to the engine. 
     
     
       9. The air cleaning system according to  claim 7 , wherein the device is an internal combustion engine whose airflow requirements are signaled by said means based on at least the operating speed of the engine. 
     
     
       10. The air cleaning system according to  claim 7 , wherein the device is a ventilation system whose airflow requirements are signaled by said means based on at least an air pressure in the ventilation system. 
     
     
       11. The air cleaning system according to  claim 1 , further comprising a compression assembly including a plurality of stationary vanes in the flow path for compressing the volume of the rotating flow of debris laden air to increase the air velocity and centrifugal force acting on the airborne particles. 
     
     
       12. The air cleaning system according to  claim 11 , wherein the compression assembly provides support for the motor-driven fan and the at least one de-swirl blade. 
     
     
       13. The air cleaning system according to  claim 11 , wherein the separator-ejector chamber in the flow path is downstream of the compression assembly. 
     
     
       14. The air cleaning system according to  claim 1 , wherein the ejector port is located in one of the downstream end of the chamber radially outward of the outlet and the outer wall of the chamber adjacent the downstream end. 
     
     
       15. An air cleaning method comprising:
 drawing particulate debris laden air into an air cleaning system with a motor-driven fan located in the system; 
 forming a rotating flow of the debris laden air about an axis in a separator-ejector chamber of the system at a positive pressure to stratify the flow with the heaviest particles in the outermost orbits of the rotating flow; 
 aerodynamically redirecting clean air from the innermost orbits of the stratified rotating flow in the separator-ejector chamber toward an outlet located centrally within the downstream end of the chamber to provide a positive airflow pressure out of the outlet; 
 returning particulate debris laden air from the stratified rotating flow in the system to the environment. 
 
     
     
       16. The method according to  claim 15 , including varying the speed of the motor-driven fan and thereby the flow rate of clean air through the outlet of the system as a function of the airflow requirements of a device being supplied with clean air by the system. 
     
     
       17. The method according to  claim 16 , wherein varying the speed includes sending a signal from the device to a controller in the system which adjusts the speed of the motor-driven fan. 
     
     
       18. The method according to  claim 15 , wherein the redirecting includes using de-swirl blades mounted in the separator-ejector chamber to aerodynamically redirect the airflow toward the outlet to provide the positive airflow pressure out of the outlet. 
     
     
       19. A powered air cleaning system for supplying clean air with a positive airflow pressure out of an outlet of the system to an air inlet of a device with which the system is used, the system comprising:
 a flow path extending through the system from an inlet to an outlet; 
 a motor-driven fan located along the flow path to draw particulate debris laden air into the inlet and rotate it about an axis to form a rotating flow that stratifies the debris laden air with the heaviest particles in the outermost orbits of the rotating flow; 
 a compression assembly located along the flow path downstream of said fan, the compression assembly including a plurality of stationary vanes in the flow path for compressing the volume of the rotating flow of debris laden air to increase the air velocity and centrifugal force acting on the airborne particles; 
 an ejector port for ejecting particulate debris laden air from the stratified rotating flow in the system; 
 means extending along the flow path from a location upstream of the eject port for aerodynamically redirecting clean air from the innermost orbits of the stratified rotating flow toward the outlet; 
 wherein the motor-driven fan includes a variable speed motor and an integrated controller for adjusting the speed of the motor and thereby the flow rate of clean air through the outlet of the system. 
 
     
     
       20. A powered air cleaning system for supplying clean air with a positive airflow pressure to an air inlet of an internal combustion engine having variable airflow requirements during operation of the engine; the system comprising:
 a flow path extending through the system from an inlet to an outlet in communication with the air inlet of the engine; 
 a motor-driven fan located along the flow path to draw particulate debris laden air into the inlet and rotate it about an axis to form a rotating flow that stratifies the debris laden air with the heaviest particles in the outermost orbits of the rotating flow; 
 a separator-ejector chamber in the flow path downstream of the motor-driven fan, the outermost orbits of the rotating flow riding on an outer wall of the separator-ejector chamber; 
 an ejector port located at a downstream end of the chamber for ejecting particulate debris laden air from the stratified rotating flow in the system; 
 means extending along the flow path from a location upstream of the ejector port for aerodynamically redirecting clean air from the innermost orbits of the stratified rotating flow toward the outlet to provide a positive airflow pressure out of the outlet to the air inlet of the engine; 
 wherein the motor-driven fan includes a variable speed motor and an integrated controller for adjusting the speed of the motor and thereby the flow rate of clean air through the outlet of the system to the air inlet of the engine; 
 the system further including means for signaling the controller as a function of the airflow requirements of the engine for varying the speed of the motor and thereby the flow rate of clean air through the outlet to the air inlet of the engine in accordance with the airflow requirements. 
 
     
     
       21. The air cleaning system according to  claim 20 , wherein the means for signaling signals the engine airflow requirements based on at least the operating speed of the engine. 
     
     
       22. A powered air cleaning system for supplying clean air to an air inlet of a ventilation system having variable airflow requirements during operation of the ventilation system, the air cleaning system comprising:
 a flow path extending through the air cleaning system from an inlet to an outlet in communication with the air inlet of the ventilation system; 
 a motor-driven fan located along the flow path to draw particulate debris laden air into the air cleaning system inlet and rotate it about an axis to form a rotating flow that stratifies the debris laden air with the heaviest particles in the outermost orbits of the rotating flow; 
 a separator-ejector chamber in the flow path downstream of the motor-driven fan, the outermost orbits of the rotating flow riding on an outer wall of the separator-ejector chamber; 
 an ejector port located at a downstream end of the chamber for ejecting particulate debris laden air from the stratified rotating flow in the air cleaning system; 
 means extending along the flow path from a location upstream of the ejector port for aerodynamically directing clean air from the innermost orbits of the stratified rotating flow toward the outlet to provide a positive airflow pressure out of the outlet to the air inlet of the ventilation system; 
 wherein the motor driven fan includes a variable speed motor and an integrated controller for adjusting the speed of the motor and thereby the flow rate of clean air through the outlet of the air cleaning system to the ventilation system air inlet; 
 the air cleaning system further including means for signaling the controller as a function of the airflow requirements of the ventilation system for varying the speed of the motor and thereby the flow rate of clean air through the outlet to the air inlet of the ventilation system in accordance with the airflow requirements. 
 
     
     
       23. The air cleaning system according to  claim 22 , wherein the means for signaling signals the ventilation system airflow requirements based on at least an air pressure in the ventilation system.